Determining residency status for U.S. tax purposes

Residency is where the return begins

Before you decide what form to file, what income to include or which credits to claim, you must answer one foundational question: Is your client a resident alien or nonresident alien for U.S. tax purposes? Residency is not a label. It is a step-by-step determination under IRS rules. Get it wrong and everything that follows can unravel. Get it right and the rest of the return falls into place.

Start with the green card test

The first question is straightforward. Did your client have lawful permanent resident status at any time during the year? If yes, they meet the green card test and are generally treated as a resident alien for tax purposes. Lawful permanent resident status typically means the individual was issued Form I-551, Permanent Resident Card, by U.S. Citizenship and Immigration Services. Once that status is granted, the taxpayer remains a resident for tax purposes unless it is formally rescinded or abandoned. As a practitioner, confirm the effective dates. Immigration timelines and tax residency do not always align neatly.

Then apply the substantial presence test

No green card? Move to the substantial presence test. This is where careful day counting matters. To meet the test, the individual must be present in the United States at least 31 days during the current year and 183 days over a three-year period that includes the current year and the two preceding years. The formula counts all days in the current year, one-third of the days in the first preceding year and one-sixth of the days in the second preceding year. If the total reaches 183 days, the client is generally a resident alien for tax purposes.

But do not stop at the math. Certain individuals are treated as exempt individuals for purposes of counting days. Some students, teachers, trainees and diplomats may exclude days if they meet specific requirements. There is also the closer connection exception, however the closer connection exception is only available if the individual is present in the U.S. for less than 183 days in the current year and does not have a pending application for lawful permanent resident status. If the individual is present for 183 days or more in the current year, the closer connection exception does not apply. 

If your clients hold a visa, like the H-1B, they are subject to the substantial presence test to determine their residency status as well. Keep in mind that treaty regulations with other countries can also affect how residency status is determined. You’ll want to review IRS regulations on how these special cases are considered.

If your client technically meets the substantial presence test but maintains stronger ties to a foreign country, they may still qualify as a nonresident. Documentation and timely filing are critical when relying on these exceptions.

Do not overlook treaty tiebreaker rules

When clients have connections to more than one country, income tax treaties can shift the outcome. A client may meet the substantial presence test and still be treated as a resident of another country under a treaty. Tiebreaker rules typically examine where the taxpayer has a permanent home, where their center of vital interests is located, their habitual abode and their nationality. If a treaty assigns residency to the foreign country, the client may take a treaty-based position to be treated as a nonresident for certain U.S. tax purposes. That position requires proper disclosure and a careful reading of the applicable treaty article. This is not an area for assumptions.

Watch for dual-status years

Midyear moves create complexity. A client who arrives in or departs from the United States during the year may have a dual-status year. That means they are a resident alien for part of the year and a nonresident alien for the other part. During the resident period, they are taxed on worldwide income. During the nonresident period, they are generally taxed only on U.S.-source income and income effectively connected with a U.S. trade or business. Dual-status returns limit certain deductions and credits and require careful allocation of income. These are detail-driven engagements where clear documentation protects both you and your client.

Match residency to the correct return

Once residency is determined, the filing path becomes clear. Resident aliens generally file Form 1040, U.S. Individual Income Tax Return, or Form 1040-SR, U.S. Tax Return for Seniors, if eligible. Nonresident aliens file Form 1040-NR, U.S. Nonresident Alien Income Tax Return. The difference is more than a form number. Resident aliens report worldwide income and may qualify for a broader range of deductions and credits. Nonresident aliens report only U.S.-source income and income effectively connected with a U.S. trade or business and face limitations on certain benefits and filing statuses.

One strategic option to evaluate is the election to treat a nonresident alien spouse as a U.S. resident for filing purposes. This can allow a married couple to file jointly and access additional deductions and credits. However, it also requires reporting the spouse’s worldwide income. As always, run the numbers and explain the long-term implications before making the election.

If a nonresident alien spouse is treated as a resident for federal tax purposes under this election, both spouses must agree to be taxed on their worldwide income (income outside the U.S.), and the election generally remains in effect for all subsequent years unless revoked. 

Build confidence in residency determinations

Residency drives the return. It affects income inclusion, deduction eligibility, credit availability and filing status. For tax professionals working with international clients, this area demands precision and confidence.

Join NATP on March 17 for the Determining Residency for Taxpayers webinar and strengthen your ability to apply the green card test and substantial presence test, including key exceptions and special rules, evaluate treaty provisions and tiebreaker rules when a treaty applies, identify and properly report dual-status years, select the correct return such as Form 1040 or Form 1040-NR and clearly explain how residency affects income reporting, deductions and credits, including when an election may allow a nonresident alien spouse to be treated as a U.S. resident for filing purposes. Register today and be ready for your next complex residency case.